Mott transition in the A15 phase of Cs${}_3$C${}_{60}$: absence of pseudogap and charge order

Abstract

We present a detailed NMR study of the insulator to metal transition induced by an applied pressure $p$ in the A15 phase of Cs${}_3$C${}_{60}$. We evidence that the insulating antiferromagnetic (AF) and superconducting (SC) phases only coexist in a narrow $p$ range. At fixed $p$, in the metallic state above the SC transition $T_c$, the ${}^{133}$Cs and ${}^{13}$C NMR spin lattice relaxation data are seemingly governed by a pseudogap like feature. We prove that this feature, also seen in the ${}^{133}$Cs NMR shift data is rather a signature of the Mott transition, which broadens and smears out progressively for increasing $(p,T)$. The analysis of the variation of the quadrupole splitting ${\nu }_Q$ of the ${}^{133}$Cs NMR spectrum precludes any cell symmetry change at the Mott transition and only monitors a weak variation of lattice parameter. These results open an opportunity to consider theoretically the Mott transition in a multiorbital three dimensional system well beyond its critical point.

References in corpus (4)

• Unconventional critical behaviour in a quasi-two-dimensional organic conductor
• Metal-Insulator Transition and Lattice Instability of Paramagnetic V2O3
• NMR study of the Mott transitions to superconductivity in the two Cs_3C_60 phases
• Exotic s-wave superconductivity in alkali-doped fullerides

Cited by in corpus (6)

• Thermodynamic and information-theoretic description of the Mott transition in the two-dimensional Hubbard model
• Coexistence of full-gap superconductivity and pseudogap in two-dimensional fullerides
• Thermodynamics of the metal-insulator transition in the extended Hubbard model
• The role of electron-vibron interaction and local pairing in conductivity and superconductivity of alkali-doped fullerides
• Manifestation of vibronic dynamics in infrared spectra of Mott insulating fullerides
• Theoretical Phase diagram of unconventional alkali-doped fullerides